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Telegraph Key
A telegraph key is a specialized electrical switch used by a trained operator to transmit text messages in telegraph systems, usually in Morse code. Keys are used in all forms of electrical telegraph systems, such as landline or "wire" electrical telegraphy, and "wireless", or radio telegraphy. An operator taps on the switch, connecting and disconnecting the electrical circuit, creating electrical pulses of two different lengths called "dots" and "dashes", to spell out text messages in code.
Since its original inception, the telegraph key's design has developed such that there are now multiple types of keys.
Straight keys
A straight key is the common telegraph key as seen in various movies. It is a simple bar with a knob on top and a contact underneath. When the bar is depressed against spring tension, it forms a circuit and allows electricity to flow.
Traditionally, American telegraph keys had flat topped knobs and narrow bars (frequently curved), while British telegraph keys had ball shaped knobs and thick bars. This appears to be purely a matter of culture and training, but the users of each are tremendously partisan. Straight keys have been made in numerous variations for over 150 years and in numerous countries. They are the subject of an avid community of key collectors.
The straight keys used in wire telegraphy also had a shorting bar that closed the electrical circuit when the operator was not actively sending messages. This was to complete the electrical path to the next station so that its sounder would operate, as in the operator receiving a message from the next town. Although occasionally included in later keys for reasons of tradition, the shorting bar is unnecessary for radio telegraphy, except as a convenience when tuning the transmitter.
The straight key is simple and reliable, but the rapid pumping action needed to send a string of dots (or dits as most operators call them) poses some significant drawbacks.
Transmission speeds vary from 5 words (25 characters) per minute, by novice operators, up to about 30 words (150 characters) per minute by skilled operators. In the early days of telegraphy, a number of professional telegraphers developed a repetitive stress injury known as glass arm or telegrapher's paralysis. "Glass arm" or "telegrapher's paralysis" may be reduced or eliminated by increasing the side play of the straight key by loosening the adjustable trunnion screws. Such problems can be avoided by using a good technique.
Our museum has a Bunnell Telegraph Key and Sounder.
J. H. Bunnell & Co
Jesse Bunnell, founder of the company to manufacture telegraph apparatus and other electrical supplies, was a kind of folk hero, a man about whom songs and stories should be written. Being born one year before Morse's invention, provided Jesse with a fertile field to become a champion telegrapher, wartime operator and establish the company, bearing his name by the age of 35.
Jesse was born in Massillion Ohio in 1843. By age 11 he was delivering telegraph messages and at 13 he was a full-fledged operator serving at offices in Ohio, Pennsylvania and West Virginia from 1859-61. He set a record at age 17 of 32 words per minute as an average, when for a steady two hours he forwarded President Buchanan's last message to Congress.
After the attack on Fort Sumter, April 1861, Jesse, not yet 18, joined the Union Military Telegraph Service (UMTS), which had been recently organized by Andrew Carnegie, who was himself an operator at age 15. At the war's start, operators were the Army's Cinderellas. They were (and remained) civilians. Their value was not appreciated, and they were given very little support and $60 per month. They were often under fire as their main duty was to relay troop movement observations and orders, in part replacing military couriers.
Moving with the Army the operator would cut his wire keeping a few yards with his instrument to reattach to the line at the next stop. During battle lulls, operators were kept busy receiving and relaying casualty information for the Army and concerned relatives. Working long hours, operators would often fall asleep at their instrument, yet always awaken when the sounder clicked their call sign.
In 1878, Jesse created J. H. Bunnell and Co. And in 1879 took Charles McLaughlin as a partner in charge of sales and administration while Jesse concentrated on manufacturing and innovations. Bunnell received a patent the 15th of February 1881 for his steel lever key. Stamped from one piece of steel, with minor machining, this was Bunnell's answer to the loosening of the steel trunnion inserted in the brass lever.
So successful, the steel lever continues to this day in keys. Early production bore the patent date on the lever. Later, this gave way to a logo containing the letters BUNNELL over a letter S, and with its general acceptance, later levers had no engraving.
In 1888, Bunnell introduced his double speed (sideswiper) key to help telegraphers avoid a "glass arm" (today called carpal tunnel syndrome). The original sideswiper, Style G, did not have spring tension adjustment. Most photographs show the style W, with a spring tensioner. Bunnell was heavily into other electricals noted an article on Bunnell Wave motor published in 1898.
Bunnell, like other companies, had their castings made for them.
With the introduction of the semi-automatic key (bug), Bunnell produced and won the right to use the generic bug. Bunnell also sold Vibroplex keys and later in association with Martin, (inventor and founder of Vibroplex) produced these bugs.
Bunnell produced for the military from the Spanish American War through the present. Bunnell made keys for Great Britain's military. Together with other companies, Bunnell produced the flameproof key, but for three decades to 1988, Bunnell was the only company to supply the flameproof to meet the Table of Equipment need of ships and planes. During W.W.II, Bunnell employed 600 people in a number of plants to produce a variety of electrical items and later supplied the military during the Cold, Korean and Viet Nam wars.
In 1899 Jesse caught a severe cold which worsened. He died of heart failure on the 9th of February 1899 at age 56. He was buried in Brooklyn's garden Greenwood Cemetery.
Vibroplex
Vibroplex is the brand of side-to-side mechanical, semi-automatic Morse key first manufactured and sold in 1905 by the Vibroplex Company, after its invention and patent by Horace Greeley Martin of New York City in 1904. The original device became known as a "bug", most likely due to the original logo, which showed an "electrified bug".
The most common Vibroplex models have a single lever with a flat thumb piece, or paddle, on the left side and a finger piece, or knob, on the right side.
The advantage of the key over a standard telegraph key is that it automatically generates strings of one of the two pulses from which Morse code characters are composed, the shortest one or "dot" (dit), so that the operator's hand does not have to make the rapid movements necessary to generate multiple dots. When the knob is pressed from the right, it makes a continuous contact suitable for sending "dashes" (or dahs, as most operators call them). When the paddle is pressed from the left, a horizontal pendulum at the opposite end of the lever is set into motion, intermittently closing a set of contacts, sending a series of short pulses "dots" (dits) at a speed that is controlled by the position of the pendulum weight. A skilled operator can achieve sending speeds in excess of 40 words per minute with a bug.
The Vibroplex Original Bug key has been in continuous production for over 100 years, with only minor cosmetic changes. Numerous Vibroplex keys are available to this day; the company presently markets and sells 27 variations of Morse code keys, including the Original Bug, iambic paddles, the Vibrokeyer (an electronic variant of the Original Bug) and traditional straight keys.
The company is located in Knoxville, Tennessee.
A Vibroplex key is found in our museum.
Telegraph Sounder
A telegraph sounder is an antique electromechanical device used as a receiver on electrical telegraph lines during the 19th century. It was invented by Alfred Vail after 1850 to replace the previous receiving device, the cumbersome Morse register and was the first practical application of the electromagnet. When a telegraph message comes in it produces an audible "clicking" sound representing the short and long keypresses – "dots" and "dashes" – which are used to represent text characters in Morse code. A telegraph operator would translate the sounds into characters representing the telegraph message.
Telegraph networks, used from the 1850s to the 1920s to transmit text messages long distances, transmitted information by pulses of current of two different lengths, called "dots" and "dashes" which spelled out text messages in Morse code. A telegraph operator at the sending end of the line would create the message by tapping on a switch called a telegraph key, which rapidly connects and breaks the circuit to a battery, sending pulses of current down the line.
The telegraph sounder was used at the receiving end of the line to make the Morse code message audible. Its simple mechanism was similar to a relay. It consisted of an electromagnet attached to the telegraph line, with an iron armature near the magnet's pole balanced on a pivot, held up by a counterweight. When current flowed through the electromagnet's winding, it created a magnetic field which attracted the armature, pulling it down to the electromagnet, resulting in a "click" sound. When the current ended, the counterweight pulled the armature back up to its resting position, resulting in a "clack" sound. Thus, as the telegraph key at the sending end makes and breaks the contact, the sounder echoes the up and down state of the key.
It was important that a sounder make a sound both when the circuit was broken and when it was restored. This was necessary for the operator to clearly distinguish the long and short keypresses – the "dashes" and "dots" – that make up the characters in Morse code.
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